Ore-roasting furnace



J. E R 0 Patented Man-:20, 1894..

UNITED STATES PATENT OFFICE.

JACOB J. STORER, OE HELENA, MONTANA, ASSIGNOR TO THE UNITED MILL ANDFURNACE COMPANY, OF MONTANA.

ORE-ROASTING F U RNACE'.

SPECIFICATION forming part of Letters Patent No. 516,663, dated March20, 1894. Application filed March 8,1893. Serial No. 465,217. on model.)

To all whom, it may concern.-

Be it known that I, JACOB J. STORER, of Helena, county of Lewis andClarke, and State of Montana, have invented certain new and usefulImprovements in Ore-Roasting Furnaces, of which the following is a full,clear, and exact description, reference being had to the accompanyingdrawings, and to the letters of reference marked thereon.

IO This invention is designed as an improvement on those ore-roastingfurnaces into which the raw ore to be operated upon is introduced fromabove in a finely pulverized condition.

Its object is to provide an improved furnace for the treatment of ores,especially forv the gold and silver'they may contain, whether they bewhat are known as pyritic or oxide ores, or whether other metals arecontained therein. By continued working with those which this inventionis designed to remedy.

To these ends the invention consistsin the peculiar construction,arrangement and combinations of parts hereinafter more particularlydescribed and then definitely claimed.

Reference is to be had to the accompanying drawings, forming part ofthis specification, in which similar letters of reference indicatecorresponding parts.

Figure 1 represents a vertical, longitudinal section of my improvedfurnace. Fig. 2 represents a sectional plan of fire places and gasexpansion chamber on lines X X Fig. 1.

In the drawings A represents the water tank constructed, preferably, ofbrick and internally cemented. Connected with this at one end and risingvertically therefrom is the furnace shaft B of cylindrical cross sectionand expanding from above downward. This shaft, which extends from theroofs of the fire places downward, consists of an exterior wall a and aninterior fire brick wall 12, between which is an annular air space 0which isclosed at both top and bottom. About the top of this shaft andconstructed so as to internally communicate with it, are fire places Ddirectly opposite each other, so constructed with sloping grates d andsloping roof f that the heat therefrom shall be radiated through their 5throats, as indicated by arrows, directly into furnaces many defectshave been developedthe vertical axis of the shaft. Openings f, that maybe closed by stoppers or doors f, are for feeding fuel into these fireplaces. In the fire place roofs are fixed stove pipes E, providedwith'dampers f which pipes serve 5 5 to carry 01f the smoke and gaseswhen the fires are first lighted.

A cylindrical pipe or conductor F, preferably of brick, is setvertically above and between the fire places, with its vertical axis 6ccorresponding with that of the shaft B.

- The tank A, as will be seen, is completely covered, partly by thefurnace shaft B, partly by an arch B having a sloping lip 19', extendinghorizontally from the furnace shaft B, and partly by a chamber or flue Bcontaining dust deflecting walls S. In the end wall of the chamber Bopenings g communicate with a spray wheel chamber G, in which is anexhaust fan H, which also serves as a spray wheel for comminuting intofine spray water that is designed to be introduced upon it, during theoperation of the furnace, through a pipe h. The exit lo from the spraywheel chamber communicates with the interior of the smoke stack L, whichlatter is filled for some distance from the bottom upward with latticeor cob work ll/L'constructed preferably of strips of wood 0, withalternating spaces 0 The combined areas of these openings or spacesbeing amply sufficient for the easy escape of all the furnace gases thatare not wetted down by the spray wheel. In the bottom of the smoke stackis shown a pipe 1) for conducting away the water that may be thrown intosaid stack and cob work. A screw conductor R, is shown in the bottom oftank A, the purpose of which is to thoroughly agitate in the water theore that is introduced through the furnace shaft, and remove it into oneor more settling pits, one of which is shown at T. v

In operating this furnace it is designed to keep the tank-A. partlyfilled with water, the

water line being indicated byldotted line W.

This furnace is designed for the heating and roasting of ores,especially those to be worked for the gold and silver they may contain.And preparatory to being introduced into the furnace they are tobefinely pulverloo ized. If an ore contains sufficient sulphur tomaintain the desired temperature in the furnace by its combustion as itfalls down the shaft, the heat and flame from the fireplaces will nothave to be supplemented by other fuel; but if the ore does not containsufficient sulphur for such purpose, pulverized coal in proper quantityis mixed and introduced with it.

In operating this furnace fires are built in the fire places and thedampers in the smoke pipes are kept open until the fuel is well ignited; then the said dampers are closed and the spray wheel is made torevolve, thus causing the flames from the fire places to be drawnclosely over the fire bridges down the interior of the shaft 13. \Vhenthe interior of said shaft has become sufficiently heated, the finelypulverized ore is introduced into the head of the shaft by a current ofair down the conductor F. On issuing from the mouth of this conductorthe descending column of air-borne ore, or mingled ore and coal, isinstantly exposed on all sides to the heat radiated from the grate firesand the sloping walls of the fire places through their wide openthroats, and is thereby at that point superficially ignited. In somecases, in the class of furnaces above referred to, as well as in thisfurnace, the flame from the fire places being drawn closely down overthe fire bridges, have little or no effect on the falling ore until thelatter has passed below the said fire bridges. But this improved furnaceessentially differs from others in the respect that in those there is nodirect radiation of heat upon the falling ore from the fire surfaces andinterior walls of the fire places; the heated air and gases aloneconveying heat into the shaft, so that none of the ore could igniteuntil it had reached and passed the fire bridges. Nor was there spacethere afforded for the necessary lateral expansion of the gasesgenerated by combustion of the ores; hence, when formed, these gaseswere violently forced downward in the line of least resistance carryingwith them the ore, a considerable portion of which would reach the waterin the tank in an insulficiently heated and but partially de-sulphurizedcondition, unless the shaft were very high, or the ore but slowly fedinto it. In this furnace, however, it will be seen that at the lower endof the conductor F, and between it and the fire bridge walls, a gasexpansion chamber V, is formed by the wide open throats of thesurrounding fire places. It is found that the hot air and gasesgenerated in these fire places and issuing therefrom, form what may becalled an elastic cushion, that yields tothe lateral expansion of thegases generated by the falling ore,sufficiently to prevent its too rapiddownward movement, so that time is there afforded to the whole mass ofthe ore for ignition at that point, and, consequently,for subsequentcomplete combustion in its passage down the shaft. Thus it is obfurnace,which vious that the gas expansion chamber is necessary for the properworking of furnacesof this class, and that it also very materiallyincreases its capacity. Falling down the shaft 13, the heavier particlesof the ore fall into the water, and settle to the bottom of the tank.The lighter particles, drawn forward by the action of the draft andspray wheel, pass beneath the arch B, which causes them to converge, sothat they are brought 1n contact with the sloping lip thereof, wherebythey are deflected downward, so that the bulk of them is thrown into thewater of the tank while still at a red heat; 1t being a very desirablematter in working some classes of ores that all the particles, ifpossible, should I enter the water at a high temperature and should notpass on to the spray wheel where they would be converted into solublesalts by the action of the sulphurous and other gases that are therewetted down by the spray. The most minute air-floated particles of ore,together with the gaseous products of combustion, pass along thehorizontal chamber or flue,-Where some of the partlcles of ore aredeflected downward into the water by the deflecting walls S,-and outthrough the opening or openings in the end of said chamber or flue, intothe spray Wheel chamber where and thrown forward,

they are wetted down with the spray into and upon the cob or latticework in the base of the smoke stack. This cob or lattice work presents avery extended surface which, when wetted by the spray, serves, incombination with it, to thoroughly condense and wet down all gases,metallic fumes and ore dust escaping from the might otherwise pass upand out of the smoke stack; and these gases and dust being thus wetteddown and held 1n so lution or suspension in water, are conducted off andout of the smoke stack to a suitable place of deposit (not shown) by apipe 19.

Having thus described my invention, what I claim, and desire to secureby Letters Pat out, is-- I 1. In a furnace constructed substantially asshown, a gas expansion chamber formed In the upper part of the oreheating and desulphurizing shaft, and fire-places surrounding the samewith wide-open throats arranged to allow the heat therefrom to act byradiation on the descending ore, substantially as described.

2. In a furnace constructed substantially as and for the purposespecified, wherein the raw ore is fed into the top of a heated shaft,the combination with said shaft, of fire places, having wide-openthroats, with their topsarranged to radiate heat directly upon thedescending ore, substantially as described.

3. In a furnace constructed substantially as and for the purposedescribed, wherein a covered water tank for the reception of thedesulphurized and oxidized ore is set beneath,

and arranged to communicate with a vertical shaft, down which, whenheated, the nulver- In testimony that I claim the foregoing I ized oreis fed, the combination with said have hereunto set my hand, in thepresence of tank and shaft, of a passage leading from the two witnesses,this 28th day of February, 1893. 10

vertical shaft over a portion of the tank and J AOOB J. STORER. 5terminating in a deflecting lip, to deflect the Witnesses:

fine air-floated particles of ore into the wa- FRANK MARTIN,

ter, substantially as described. JOHN H. FARMER.

